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Proučevali smo vpliv nihajočih klimatskih razmer na staranje lesa. Pri tem smo uporabili dva predstavnika iglavcev (smrekovina, macesnovina), ter tri predstavnike listavcev (hrastovina, jesenovina, bukovina). Spremenljive klimatske razmere smo simulirali v napravi za umetno pospešeno staranje (UPS) v 500 ciklih obremenjevanja. Med cikličnimi spremembami smo spremljali maso, dimenzijske spremembe radialnih in tangencialnih preizkušancev, dinamiko barvnih sprememb ter čas pojavljanja in razširjenost razpok in veženja. Hrastovina in macesnovina sta imeli najboljšo oceno. Pri smrekovini je kot pomembna izstopala orientacija z velikimi razpokami tangencialnih preizkušancev. Dimenzijsko najmanj stabilna je bila bukovina, tudi z izrazito koritavostjo. Barvne in dimenzijske spremembe so bile najintenzivnejše po prvem intervalu izpostavitve. We studied the effects of changing climatic conditions, which have influence on the aging process of wood. We used two representatives of softwoods (spruce wood, larch wood), and three representatives of hartwoods (oak wood, ash wood, beech wood). Variable climatic conditions were simulated in a device for artificial accelerated aging (QUV weathering tester) over the course of 500 cycles. During the cycles, we measured the mass, dimensional changes in radial and tangential direction, the dynamics of colour variation, and the time of occurrence and prevalence of cracks and warping. Oak wood and larch wood had the best overall assessment. On spruce samples it stood out large cracks that have occure on tangential oriented samples. As expected, beech wood was the least dimensionally stable, also with distinct cupping. The color changes and dimensional changes, have been the most noticeable after the first phase of exposure. |
